Help with PLLXO for F.A.S.T, CHR-70+DA175-8

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Need some help please as I lack any knowledge of passive line-level crossover design. Had a look at:
TLS.org | Passive Line-Level Crossover
but it's way over my head, maybe to many years since I was in school :confused:

Mid/High driver is Mark Audio CHR-70, mounted in a 1lit plastic sphere, trawl float.
Low freq will be covered with Dayton DA175-8 in a 16lit sealed PVC pipe.

Crossover freq 300Hz but other ideas are welcome. First order 6 dB.

Amp for DA175-8 is Hifimediy T1, Input impedance: 50K
Amp for CHR-70 is Hifimediy T1-M, Input impedance: 50K

Source is my laptop to a HifiMeDiy Sabre USB DAC. 96khz/24bit

The system is for my camper/RV.

Pictures will be posted soon as I progress with the construction.
 
Problem solved.
It seems to be more attractive for members to discuss their view in the thread on passive vs. active filters than to help out with the construction of an actual filter.
85 members have had a look on this topic but left no reply.
This time google was more of an help than here.
Have fun! :cool:
 
Problem solved.
It seems to be more attractive for members to discuss their view in the thread on passive vs. active filters than to help out with the construction of an actual filter.
85 members have had a look on this topic but left no reply.
This time google was more of an help than here.
Have fun! :cool:

Hi Tachyon,

You need a measurement mike (~50 £ or 600 SEK), a soundcard with phantom power for the mike and start by doing measurements. Use ARTA or some other software suite and get familiar with it.
The PLLXO math is pretty straight forward but there is a spreadsheet out there you can download. I made one for myself way back that I can send you.
The PLLXO must be driven from a preamp with low output impedance and a healthy output voltage since there is going to be insertion loss in the filter.

best
Kris
 
Hi Kris,
found the spreadsheet and figured out the values, thanks.

My initial plan is not to use a preamp as this is a mobile setup
Laptop -> USB DAC -> PLLXO -> Class D Amps -> drivers

This is the only specs I have found so far for the DAC, has it enough juice for the PLLXO?

Output power on different loads:

Open 2.2Vrms
4.7k 2.1Vrms
1.8k - 1.9Vrms
510R 1.5Vrms
330R 1.3Vrms
30R 1Vrms

Regards
Ralph
 
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